Searches not displaying every product related to my request.

The search in question for "sheet music" it says there is 18,000 used items and over 1,000+ not specified in "all categories" but when option is selected to only used & unspecified, it then only displays 1,200+ and not all current "new listings" for either of these.....they can only be seen if you also keep the "new" in the setting which displays 25,000+ listings and that then means longer scrolling time to find all new USED listings.